Time switch



April ze, v1949. H. L. EMERY Y 2,468,548

TIME SWITCH Filed April 24, 1946 1115. 21 TILT -Hq.` 3

Patented Apr. 26, 1949 UNITED STATES PATENT OFFICE 4 Claims.

This invention relates to a time switch for an electric circuit and isparticularly applicable to washing machines, electric toasters, waflleirons, electric stoves, and other home appliances, and which is readilyoperable by manua-l means to predetermine the interval of delayed actiondesired by the operator.

The invention has to do with a device operating somewhat on the dashpotprinciple, but wherein its delaying action is controlled by frictionalresistance. Thus the effect of gravity is negligible, whereby the switchwill operate in any position independent of gravity, and its operationis independent of all elevational and barometric pressure variations.

It is an object of the invention to effect an improvement over theconventional dashpot device and to lessen the possibility of failurepeculiar to the conventional type of switch. This is accomplished bybiasing the contact member against frictional resistance.

It is a further object of the invention to produce a device which issimple in construction and, therefore, inexpensive to produce.

Another object of the invention resides in the arrangement of acombination snap and delayed action switch permitting the operator toemploy either feature as and when he desires.

The full nature of the invention will be understood from theaccompanying drawings and the following description and claims.

Fig. l is a plan view of the time switch.

Fig. 2 is a longitudinal sectional view thereof taken on the line 2 2 ofFig. 1.

Fig. 3 is a bottom plan view of the time switch.

Fig. 4 is a side elevation view of a modification of the time switchwith parts broken away.

Fig. 5 is a vertical section view thereof.

Fig. 6 is a plan view thereof taken on a line 8--6 of Fig. 5.

Fig. '7 is a section view thereof taken on a line 1-1 of Fig. 6.

In the drawings for the purpose of illustrating an application of theinvention, the delayed action or time switch is shown housed in a casingIU having a removable cover plate II suitably secured in position bymeans of screws.

The switch mechanism comprises a confining friction member, here shownas a cylindrical tube I2, which is open at both ends and is secured tothe cover plate by means of screws I3 and I4. Slidable within the tubeis an expansible friction element here shown as a plunger I5, connectedto a shaft I6 which is supported at one end by the bearing I1 secured tothe cover plate 1 by means of screw I8. The shaft is secured to asupporting bracket I9, which has a control arm 2U extending through aslot 2I in the cover plate, by the set screw 23. To the end of the arm20 there is secured a manually operable knob 24 by means of anchor screw25.

Threaded to the shaft near one end thereof and abutting a washer 22which separates it from the plunger I5, there is a compression nut 26which may be rotatably adjusted by the operator through the slot 21 inthe casing either to compress or release the plunger to thereby increaseor decrease the frictional resistance of the plunger.

Biasing the eXpansible plunger towards one end of the friction tube aretension springs 30 and 3l which are supported at one end by the base 32of rack 33 and at the other end by bracket 34 which is secured to thecover plate by screw 35.

The base 32 of rack 33 has an aperture intermediate both ends throughwhich protrudes the reduced end 28 of the shaft. The rack 33 is held inmesh by boss 29 with pinion 35 which controls the movement of the timeindicator 36.

As the operator manually adjusts the stroke of the plunger I5 throughthe medium of knob 24 he causes it to move away from the Contact strip31 against the resistance of the springs 30 and 3l. When the operatorreleases the knob, the tension of the springs overcomes the frictionalresistance between the expansible friction plunger and the tube I2 andcauses said plunger to move rearwardly towards the switch controlelements.

Electric contact elements 38, 39, 46, and 4I are suitably insulated andadapted to be electrically connected into any electric circuit. Contactstrip 31, preferably formed of spring metal, is secured to terminal 39and is engageable with terminal 38. As the expansible friction plungerapproaches the Contact strip, the means operatively connected with it,here shown as an insulated stem 42 at one end of the shaft, engages withthe contact strip and causes it to become disengaged from terminal 38thereby breaking the circuit.

Figs. 4, 5, and 6 show a modified form of the invention which combinessnap and delayed action means. A casing 43 is secured to a Wall hanger44 which has a slot therein permitting an over center operable camswitch 45 supported by bearing 4G and pivoted at 41, to move freely toand from therein.

The expansible friction element, here shown as a plunger 48, hasfrictional engagement with the innel1 walls of a confining member, hereshown as a cylindrical tube 49, which is open at one end. The plunger issecured to a shaft 50, which is freely slidable within said tube andmounted in an insulated bearing plate 5|, which is separated from theplunger by bushing 52. The frictional resistance of the plunger may beincreased or decreased at will through an adjustment of nut 53. Springs54 and 55 cause the plunger to move against its frictional resistance.

Electric contact elements 55, 51, 58, and 59 are adapted to beelectrically connected into any electric circuit. Contact strip 5@ issecured to plate Si and is engageable with plate S2.

When it is desired to employ the snap action feature of thismodification, the operable cam switch is moved by the operator to theposition shown in Fig. 4. r1"'he cam face engages the shaft 5! andforces the insulated bearing plate downwardly out of engagement withcontact strip 60 permitting said contact strip to become engaged toplate E2 thereby completing the circuit.

When the operator desires to employ the delayed action feature of themodification, he moves the cam switch member 5 forwardly as far as itwill go. The cam face 53 Gf the cam switch member engages the shaft 55and forces it downwardly against the resistance of the springs 5d andThe operator then moves the switch member back to the position shown inFig. 5. The tension of the springs gradually overcomes the frictionalresistance of the plunger and causes the insulated bearing plate 5! toengage the contact strip 5d and disengage said strip from plate 52,thereby breaking the circuit.

I claim:

l. In an electric time switch including a housing, a stationary electr'cContact on said housing, a movable contacto-r engageable therewithbiased in one direct-io e tension of biasing spring direction, theccation theren .lng tubular memo-er having an on surface, a frictioelement havly expansibie head of friction material in said tubular r.ember in restrain- .il engagement with its friction surans operablyconnecting said fricnt with said contactor whereby upon being moved in adirection opposed to the bias of said contactor the friotionalresistance thereof will delay its movement from Contact engaging tocontact breaking positions.

2. In an electric time switch including a housing, a stationary electriccontact on said housing, a movable contactor engageable therewith biasedin one direction under tension of a biasing sping and an actuator formoving said contactor in tbe opposite direction, the combinationtherewith of a cylindrical well formed in said housing, said well.having a confining and restraining friction surface, a friction elementhaving a head of expansible friction material movable within well infrictional engagement with its coniining and restraining frictionsurface, and means operably connecting said friction element with saidcontactor whereby upon being moved in a direction opposed to the bias ofsaid contactor the frictional resistance thereof will delay its movementin the biased direction.

3. In an electric time switch including a housing a stationary electriccontact on said housing, a movable contactor engageable therewith biasedin one direction under tension of a biasing spring and an actuator formoving said contactor in the opposite direction, the combinationtherewith of a confining tubular member having an internal frictionsurface, a friction element having a radially expansible head offriction material movable within said tubular member in restrainingfrictional engagement with its friction surface, regulating mechanism inengagement with opposite sides of said friction head to axially compressit in a direction to vary its effective diameter relative to saidtubular member for regulating the time delay from actuated to actuatingposition, and means operably connecting said friction element with saidcontactor whereby upon being moved in a direction opposed to the bias ofsaid contactor the frictional resistance thereof will delay its movementin the biased dir ction.

4. In an electric time switch including a housing, a stationary electricContact on said housing, a movable contactor engageable therewith biasedin one direction under tension of a biasing spring and an actuator formoving said contactor in the opposite direction, the combinationtherewith of a restraining member on said housing having a frictionsurface, a friction element movable relative to said member inrestraining frictional engagement with its friction surface, a timesetting device in operative engagement with the biasing spring to varythe tension thereof relative to the frictional resistance between saidfriction element and restraining member, and means operably connectingsaid friction element with said contactor whereby upon being moved in adirection opposed to the tension of said biasing spring the frictionalresistance of said member will delay its movement in the biaseddirection.

HARVEY L. EMERY.

REFERENCES CITED The following references are of record in the le ofthis patent:

UNITED STATES PATENTS Number Name Date 743,160 Herman Nov. 3, 19031,834,984 Steinmayer Dec. 8, 1931 1,879,169 Friedinger Sept. 27, 19322,202,297 Mudon May 28, 1940 FOREIGN PATENTS Number Country Date 640,009Germany Dec. 9, 1934

